The present invention relates to dental equipment, and especially to a dental handpiece which carries a supply of dental paste to be delivered to a patient's mouth in conjunction with the performance of a teeth cleaning operation. The invention also relates to a method of cleaning teeth.
In the performance of teeth cleaning operations, a prophy cup is rotated at the end of a handpiece to scrub the teeth with a paste. It is necessary to frequently transfer the prophy cup from the patient's mouth to a paste container in order to refill the prophy cup with paste. Such a practice interrupts and prolongs the cleaning operation.
In an effort to alleviate that shortcoming, it has been previously proposed to integrate a paste supply with the dental handpiece and provide mechanical power for delivering the paste to the patient's mouth, e.g., see U.S. Pat. Nos. 2,400,912; 2,738,528; 3,987,550; and 4,220,446.
For example, U.S. Pat. No. 2,400,912 discloses a handpiece possessing an internal paste chamber which communicates with a prophy cup by means of an external flexible conduit. A linearly movable plunger disposed within the paste chamber is displaceable by a mechanical take-off from the drive train which rotates the prophy cup. By displacing the plunger, paste from the chamber is forced through the conduit and into the prophy cup.
In U.S. Pat. No. 3,987,550 and U.S. Pat. No. 4,220,446 dental handpieces are disclosed wherein paste is stored within an external container secured to the handpiece. A plunger extends into the container and is actuated by pressurized fluid such as air or water, in order to dispense the paste. The pressurized fluid is admitted to the plunger by means of a hand or foot actuated valve.
U.S. Pat. No. 2,738,528 discloses a handpiece in which a squeezable paste container is mounted on the exterior of the handpiece casing. An external conduit leads from the container to the prophy cup. By manually squeezing the container, paste is able to be delivered to the prophy cup.
It will be appreciated that the handpieces disclosed in the aforementioned patents involve certain drawbacks. For example, the provision of external containers and/or conduits makes the handpiece cumbersome and more difficult to maneuver about a patient's mouth. Also, the need to provide auxiliary means of power to eject the paste adds expense and complexity to the system, as does the need to provide extra components such as plungers and hand or foot controls for example. It is also inconvenient for the operator to have to manipulate a foot or hand control in order to dispense the paste.